An independent, peer reviewed journal for policy makers and practitioners in agriculture and related industries, assessing the interactions between population growth, resources, the environment and climate change.

Author: Professor Vaclav Smil

Summary
In the biosphere nitrogen has the most complex cycle of all circulating elements.
Its incessant reuse makes life on Earth possible. Traditional agricultures supplied limited amounts of the nutrient by recycling organic wastes and by planting leguminous crops.
Only the Haber-Bosch synthesis of ammonia, first commercialised in 1913, removed this key constraint on crop productivity.
Global agriculture has become steadily more dependent on synthetic nitrogenous compounds …